Method of making a rotary switch stator

ABSTRACT

A method of manufacturing a rotary switch stator in which round section wire used for the stator pins is formed into meander loops which are placed in a mold so that certain portions of the meander are held in radial formation and other portions are held in parallel arrangement whilst the intermediate interconnecting portions are within the annular cavity of the mold which is filled with liquid electrically insulating material. After the insulating material has solidified, the excess parts of the wire are cut off to leave a stator having a plurality of equi-spaced radial contact studs and the same number of parallel electrical contact members respectively connected thereto.

United States Patent 1191 Deltoer Mar. 26, 1974 [54] METHOD OF MAKING AROTARY SWITCH 3,261,929 .7/1966 Neff 200/1 1 D STATOR 3,219,785 11/1965Allisonm 200/11 D 3,011,041 11/1961 Bakels.... ZOO/DIG. 7 [76] Inventor:Marcel Henri Deltoer, 22 rue 2 73 ,935 3 1957 Mammy mg 7 Ravon, Hauts deSeine, France 2,668,894 2/1954 Coutcs ZOO/166 CM [22] Filed: Feb. 23,I973 Primary ExummerCharles W.- Lanham 1 pp NOJ 335,171 AssistantExaminer.lames R. Duzan Attorney, Agent, or FirmStevens, Davis, Miller &

[30] Foreign Application Priority Data Moshe! 4 Mar. 24, 1972 France7210428 [57] ABSTRACT [52] 29/630 29/597 29/622 A method ofmanufacturing a rotary switch stator in 29/630 zoo/166 CM which roundsection wire used for the stator pins is [51] Ill. Cl H01! formed intomeander op which are placed in a mold [58] held of Search 29/622 630 630597; so that certain portions of the meander are held in ra- 200/11 166166 dial formation and other portions are held in parallel 310/237;339/5 5 5 P arrangement whilst the intermediate interconnecting portionsare within the annular cavity of the mold [561 References cued which isfilled with liquid electrically insulating mate- UNITED STATES PATENTSrial. After the insulating material has solidified, the ex- 3.599.3258/1971 Burr 1 29/597 cess parts of the wire are cut off to leave astator hav- 3,548.123 12/1971) Allison ZOO/1 1 ing a plurality ofequi-spaced radial contact studs and 3-539-854 11/1970 Futterer 9 a310/233 the same number of parallel electrical contact mem- 3,529 3489/1970 Kucharskin. 1. 29/597 b respectively connected thereto 3524.2508/1970 Burr v 2 /597 v14711.1 x0 11/1969 Bang 200/1 1 D 4 Claims, 4Drawing Figures PATENTED HARZB I874 SHEEI 1 BF 2 METHOD OF MAKING AROTARY SWITCH STATOR FIELD OF. INVENTION The present invention relatesto a method of producing a stator element for a miniature rotary switch,and the stator element so produced. A switch constructed using thedesign of the present invention is suitable for direct mounting on astandard predrilled printed circuit board.

DESCRIPTION OF THE PRIOR ART Known methods of producing rotary switchstators usually start with a metal sheet from which is stamped theconductor elements these individual elements being held together by partof the said sheet not required by the stator conductors in'their finalform, this excess material being removed after the elements have beenmolded into the stator assembly. The molding forms a'hollow insulatingbody through which the stator contacts conduct electricity from externalconnections to the moving central assembly of the switch.

Such a construction has the disadvantage that the contact studs formedby the inner ends of the stator conductors are relatively-fragile andthe contacts are subject to electrical losses.

An improvement to the above construction is described in my French Pat.No. 1,398,866 wherein the conductive stator elements are manufactured bypreforming round wire to the shape of a'multi-point star closed onitself, which is incorporated and centred in the mold of the statorelement. The reentrant sections of the star extending towards the centreof the assembly are trimmed to separate them and constitute the roundedcontact studs and the conductive elements are rendered separateexternally by cutting off the excess conductor.

The disclosure in my French Pat. No. 1,398,866 is an improvement in thepreviously known prior art in that it uses a round wire which canconsist of either a solid precious metal or be plated with such a metaland has no surface roughness which might be conducive to electricbreakdown and losses.

The disadvantage of the switch stator made in accordance with thepreviously known prior art is that the disposition of the connectionsexternal to the switch these being around the periphery of the stator,is not suitable for many applications.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a rotary switch stator element using round section electricalconductors which conductors are brought out of one flat external face ofthe stator molding in a manner suitable for their direct insertion in astandard predrilled printed circuit board.

According to the present invention there is provided a method ofmanufacturing a rotary switch stator including the steps of:

a. bending at least one wire to form a plurality of meander loops havingarcuate portions at the ends interconnecting long rectilinear portions;

b. taking the meander loops at one end and arranging parts to form aplurality of rectilinear portions in equi-spaced relation in a circleand radially aligned with respect to the centre of the circle;

c. arranging the remaining parts of the meander loop in parallelarrangement whereby a number of intermediate connecting parts areprovided between the radial parts and the parallel parts;

(I. holding said radial parts and those portions of said parallel partsadjacent said intermediate parts in fixed relation;

e. placing said intermediate parts in a molding zone;

f. pumping into said molding zone, electrically insulating material inliquid form; g. allowingsaid liquid to set within the molding zone;

h. removing the resulting cast stator element from said molding zone;

. cutting away the inner arcuate portions joining the radial portions soas to leave a plurality of equispaced contact studs; and

j. cutting away the excess parts of the parallel portions of the meanderloops so as to leave a corresponding number of electrical contactmembers.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now bedescribed in greater detail by way of example with reference to theaccompanying drawings, wherein:

FIG. I is a plan view ofa round wire bent in a plane;

FIG. 2 shows two superposed wires one being of the form of FIG. 1, theother being a mirror image of the first;

FIG. 3 is a sectional view rated in a mold; and

FIG. 4 is a perspective view of a stator element produced in accordancewith the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the wire Ais bent into the shape shown which shape comprises three bent loops 1,2, 3, which are joined by the semi-circular rounded sec tions 4 at theirouter ends, to form a hairpin-shaped element, so that, with the two ends5 and 6 of the wire,

the four rectilinear portions 7 form six parallel rectilinear branches.

The central arms 2 are shaped such as to comprise two rectilinearsections 8 and 8a joined by a rounded section 9, the rectilinearsections being radial in relation to the centre 0 there being an angle 3of between them.

The two external pairs of arms 1 and 3 are bent over at their inner endstowards the central arms 2 and each comprise two rectilinear radialsections 8 joined by the arcs 9, the said radial sections being at anangle of 60 to one another with two neighbouring rectilinear sections 8,belonging to two different loops, also having an angle of 60 betweenthem.

Thus there is obtained around the centre 0 six rectilinear radialsections which are equi-angularly spaced and which, assuming the wholeto be incorporated in a molded member B, can provide, after severing ofthe arcs 9 along the circle ll,six contact studs within the cavity ofthe molded member'B, which correspond to the six pins obtained after thesevering of the two semi-circular sections 4. v

If only six conductor elements, each comprising one pin, one stud andthe intermediate section embedded of the two wires incorpoin thematerial of the member B, are used, the two pairs of arms I and 3 may bepositioned symmetrically about the central arms, which are also ofsymmetrical form. V

However, in the illustrated embodiment, the ends of the three pairs ofarms incorporated in the molded member B are deformed to correspond to arotation of all the elements 8 through relative to the axis XX in theplane of the member B and about the centre 0.

Thus, the rectilinear section 8a is at an angle a of exactly 15 with thesaid axis XX.

Hence by the superposition of two wires A and C which are both shaped aswire A of FIG. 1 but one of which is turned over in relation to theother, it is possi ble to obtain twelve radial sections 8 which arespaced apart by 30, and which correspond to twelve pins lying in twoparallel planes.

Referring now to FIGS. 2 and 3, there is shown an example of a moldassembly which enables two flat wires shaped as above to be incorporatedin a molded member.

The mold illustrated in FIG. 3 comprises a base 12, an intermediatesection 13, a top section 14 and a central core 15, the elements 12,13and 14 being secured together by means of pins 29. Tile mold base 12 isprovided with an injection orifice 25, and a central annular part 16 onthe top of which there are cut 12 radial slots 17 of semi-cylindricalform, which are intended to receive the 12 radial sections 8 of the twobent wires A and C. In addition, the edge of the base 12 is formed withsix rectilinear slots 18 running perpendicular to the said edge, whichreceive the rectilinear sections 5, 6 and 7 of the wire A.

The intermediate section 13 is formed with six slots 19 in registrationwith the slots 18 in the face of the base 12, and six other slots 21 inthe face directed towards the cover 14, which latter slots areinterspaced, as seen in plan view, between the mentioned slots (18 and19) and receive the rectilinear sections 5, 6 and 7 of the wire C. Thecover 14 is formed with six slots 22 opposite the slots 21 and a centralbore 23 to enable thecore 15 to be slid in and out of the mold.

To produce a stator element, the components of the mold having beenplaced one above the other but spaced apart from one another, the wire Ais first placed in one-half of the slots 17 and 18. The section 13 isthen lowered onto the base 12, and there is then placed on this sectionthe wire C, still in the flat state, which is clamped parallel to theplane of the wire A by the cover 14 which is pressed against the sectionand the base.

Next, the core 15 is pushed into position and is prevented from rotatingin relation to the remainder of the mold by suitable means (notshown).-The end of the core 15 has formed in it the radial slots 32which match the slots 17. When it engages the rectilinear sections 8 ofthe wire C, the pairs of arms, 1, 2 and 3 of the said wire are bentdownwards and the curved sections 26 and 27 (FIG. 2) of the wire arebent as illustrated in FIG. 3 within an annular cavity 28 bounded by thecore 15 formed the inner wall and the elements 12, 13 and 14 forming theouter wall.

Next, a suitable electrical insulating material in liquid or semi-liquidform is pumped into the annular cavity 28 through the injection orifice25, said material then solidifying in the course of time. After thesolidification of the insulating material injected into the cavity 28,the various wire sections 7 are permanently located in the positionsillustrated in FIGS. 2 and 3.

It is to be noted that, by reason of the superimposition in differentplanes of the wires A and C, there is always a substantial thickness ofinsulating material between any two wires embedded in the molding.

Finally, the molding is released and trimmed and the rounded arcs 9within the cavity 30 of the molded member B are cut off in a press, theouter arcs being similarly removed and the molded article shown in FIG.4 is obtained. The twelve rectilinear sections 8 project radially intothe cavity 30 and each of them is contiguous with one pin (5, 6 or 7),the parallel pins being disposed to form two sets of six equi-distantpins in two parallel planes. These pins are arranged in two rows whichare staggered in relation to one another with a uniform square spacingof 2.5 mm, which is the standard spacing for weak-current printedcircuit cards.

The radial sections 8 are advantageously turned down as shown or bent ina press so as to be spaced apart and more suitably shaped to enable amovable contact member to slide over them. If the pins 5, 6, 7 areintended to have conductors fixed thereon by wrapping they may be of thelength shown in the drawings. If the connecting conductors are solderedto these pins, they may be shortened and the wire may be bent to thelength defined by the rounded portions 4a.

Finally, the cavity 30 may include a shoulder 31 forming a bearing forthe rotor.

The invention is applicable to the production of miniature contactors,such as those used in the. complex electronic circuits produced onparallel spaced-apart cards, on which they are mounted circuitsassociated with electronic components.

What I claim and desire to secure by Letters Patent 1. A method ofmanufacturing a rotary switch stator including the steps of:

a. bending at least one wire to form a plurality of meander loops havingarcuate portions at the ends interconnecting long -rectilinear portions;

b. taking the meander loops at one end and arranging parts to form aplurality of rectilinear portions in equi-spaced relation in a circleand radially aligned with respect to the centre of the circle;

c. arranging the remaining parts of the meander loop in parallelarrangement whereby a number of intermediate connecting parts areprovided between the radial parts and the parallel parts;

d. holding said radial parts and those portions of said parallel partsadjacent said intermediate .parts in fixed relation;

e. placing said intermediate parts in a molding zone;

f. pumping into said molding zone, electrically insulating material inliquid form; g. allowing said liquid to set within the molding zone;

h. removing the resulting cast stator element from said molding zone;

' i. cutting away the inner arcuate portions joining the radial portionsso as to leave a plurality of equi spaced contact studs; and

in two parallel planes whereby the resulting contact members after themolding and cutting operations are located in two parallel rows ofcontacts, the elements of one row being staggered in relation to thoseof the 1 other row.

3. The method according to claim 2, wherein there are 12 radial partsfor forming l2 equispaced radial contact studs, and the contact elementsare arranged in two rows of six.

4. The method accordingto claim 2, further comprising: compressing theradial parts of the two sets substantially in the same plane parallel tosaid parallel planes.

1. A method of manufacturing a rotary switch stator including the stepsof: a. bending at least one wire to form a plurality of meander loopshaving arcuate portions at the ends interconnecting long rectilinearportions; b. taking the meander loops at one end and arranging parts toform a plurality of rectilinear portions in equi-spaced relation in acircle and radially aligned with respect to the centre of the circle; c.arranging the remaining parts of the meander loop in parallelarrangement whereby a number of intermediate connecting parts areprovided between the radial parts and the parallel parts; d. holdingsaid radial parts and those portions of said parallel parts adjacentsaid intermediate parts in fixed relation; e. placing said intermediateparts in a molding zone; f. pumping into said molding zone, electricallyinsulating material in liquid form; g. allowing said liquid to setwithin the molding zone; h. removing the resulting cast stator elementfrom said molding zone; i. cutting away the inner arcuate portionsjoining the radial portions so as to leave a plurality of equi-spacedcontact studs; and j. cutting away the excess parts of the parallelportions of the meander loops so as to leave a corresponding number ofelectrical contact members.
 2. The method according to claim 1,including: forming a second set of meander loops of identical form tothe first set; placing the radial parts of the second set in between theradial parts of the first set so that all the radial conductors areequi-spaced in the circle; and holding said parallel parts of the firstand second sets in two parallel planes whereby the resulting contactmembers after the molding and cutting operations are located in twoparallel rows of contacts, the elements of one row being staggered inrelation to those of the other row.
 3. The method according to claim 2,wherein there are 12 radial parts for forming 12 equispaced radialcontact studs, and the contact elements are arranged in two rows of six.4. The method according to claim 2, further comprising: compressing theradial parts of the two sets substantially in the same plane parallel tosaid parallel planes.